Lens holder for metallic blocking system



Nov. 21, 1967 5. M. J. SAROFEEN 3,353,307

LENS HOLDER FOR METALLIC BLOCKING SYSTEM Filed Oct. 29, 1964 2Sheets-Sheet l INVENTOR ATTORNEYS Nov. 21, 1967 G. M. J. SAROFEEZN3,353,307

LENS HOLDER FOR METALLIC BLOCKING SYSTEM Filed Oct. 29, 1964 2Sheets-Sheet 2 INVENTOR ATTORN E Y5 United States Patent 3,353,307 LENSHOLDER FOR METALLIC BLOCKING SYSTEM George M. J. Sarofeen, ColonialHeights, Va., assignor to Titmns Optical Company, inc, Petersburg, Va.,a corporation of Virginia Filed 0st. 29, 1964, Ser. No. 407,376 27Claims. (Cl. 51-216) ABSTRACT OF THE DISCLOSURE A lens blocking memberhaving a base and non-flexible side walls which receive a blockingagent, preferably a low-melting metallic blocking agent, and a lensblank spaced from the base wall. The lens block, when mounted on a lensprocessing apparatus, enables precise axial measurements between theapparatus and points on the surface of the lens. One preferredembodiment includes a flexible gasket having an annular flange whichextends above the base wall of the blocking member into engagement withthe lens blank for forming a cavity into which the blocking agent isinserted.

This invention relates to a lens blocking member for use in a lens blankblocking system and more particularly to a lens blocking member wherebya precise axial spacing between a surface of the lens blank and the lensprocessing apparatus may be established.

When grinding a lens blank, the essential problem is one of reference.Multiple curves can only be put on the lens blank if there are referencepoints so that the particular axes of each curve can be located.Thickness control is another problem which can only be controlled byestablishing a means of reference between the grinding apparatus and thelens blank surface itself. The lens blank may be ground to uniformthickness or to a varying thickness which leaves a prismodal effect onthe lens blank.

A surface of known curvature may be ground on a lens blank; however,when a surface is ground on the opposite side of the lens blank, it isextremely difl'icult to fix the lens precisely for controlling thicknessand prism effects with relation to the first groundsurface and also tofix the lens precisely for establishing accurate axes from which tolocate compound curves on the lens blank. By establishing points ofreference from one surface of the lens to the block member by which itis held and thereafter through the grinding apparatus to the surface ofthe grinding lap, the variables in the unground surface may beeliminated from consideration and the lens may be precisely oriented. Aprecise axial distance is established between the surface of thegrinding lap and the base wall of the blocking member through theinternal structure of the lens grinding apparatus. Therefore, it is anobject of this invention to provide means by which an accurate axialdistance may be established between the inwardly facing or previouslyground surface of the lens blank and the base wall of the blockingmember itself so as to interrelate the positions of the inwardly facingsurface of the lens blank and the surface of the grinding lap.

It is a further object of this invention to provide a blocking memberfor use with a lens blocking system which has a base wall having frontand back sides with a side wall depending from the front side of thebase wall forming a first cavity between its inwardly facing surface andthe front side of the base wall. The cavity preferably receives a lensblank and a low-melting metallic agent, although it 'will be appreciatedthat any type of blocking agent may be used within the scope of thisinvention, for holding the lens blank. Means associated with the basewall are provided for engaging and positioning the lens blank at leastpartially within the cavity and for spacing the lens blank apredetermined known distance from the back side of the base wall so thata precise axial spacing between a .point on the inwardly facing surfaceof the lens blank and the lens processing apparatus may be established.Accordingly, the thickness between the inwardly facing surface and theoutwardly facing surface may be precisely regulated.

It is also an object of this invention to provide the inwardly facingsurface of the side wall with means cooperating with the edge of thelens blank for positioning the lens blank in a predetermined orientationwithin the blocking member.

Further objects of the invention include a means, e.g. a port, to permitthe blocking agent to be inserted into the cavity. If a low-meltingmetallic blocking agent is used, it will be appreciated that for economypurposes the provision of a surface corresponding to the inwardly facingsurface of the lens blank is desirable as a means of limiting the volumeinto which the blocking agent must be inserted.

It is a further object of this invention to provide gasket meansassociated with the front side of the base wall and having at least anannular wall extending away from the front side so as to form a secondcavity concentrically within the first cavity. It will be seen that thisgasket means limits the volume of the blocking agent required and alsoprovides protection for the lens positioning means by preventing theblocking agent from covering the positioning means so as to prevent thelens from seating contiguously on the" positioning means, thus varyingthe otherwise known spaced relationship between the lens blank and theholder.

It is a further object of this invention to provide a gasket meanscomprising a base means and an annular side wall depending from the basemeans having its outer edge portion outwardly flared. It will beappreciated that the base portion of the gasket may comprise a flat ringwall which is received in a recess in the front side of the base wall ofthe blocking member. Accordingly, if the recess for receiving the gasketmeans is adjacent to the side wall, the base wall of the gasket meansmay be so configured as to engage the inwardly facing surface of theside wall and the supporting means which may be integrally formedtherewith.

As a further object of this invention, the lens supporting meanscomprise a plurality of lugs spaced along the inwardly facing surface ofthe side wall of the blocking member.

Still another object of the invention is to provide a blocking member asdescribed having means by which the same may be mounted on the lensprocessing apparatus O in a predetermined desired orientation. Suchmounting means may include a raised handle member depending from theback side of the lens block which has keying means associated therewithso that the supporting element of the processing apparatus can maintainthe lens block in a predetermined desired orientation.

These and other objects of this invention are more clearly depicted inthe following detailed description having specific reference to theattached drawings in which the embodiments of the invention are shown,not to limit the scope of the invention in any respect but that theprinciples thereof might be more clearly demonstrated.

In the drawings:

FIGURE 1 is a side elevation view of the blocking member shownschematically in use with a grinding lap and lens processing apparatus;

FIGURE 2 is a top plan view of the blocking member;

FIGURE 3 is a bottom plan view of the blocking member;

FIGURE 4 is a sectional view taken substantially along the lines 44 ofFIGURE 2;

FIGURE 5 is a sectional view taken substantially along the lines 55 ofFIGURE 2;

FIGURE 6 is a perspective view of the gasket means;

FIGURE 7 is a top plan view of a modified blocking member;

FIGURE 8 is a sectional view taken substantially along the lines 88 ofFIGURE 7;

FIGURE 9 is a bottom plan view of the modified blocking member shown inFIGURE 7; and

FIGURE 10 is a fragmentary sectional view of the blocking member shownin use with a polishing lap.

In FIGURE 1, the improved lens blank blocking member is shownschematically in use with a grinding lap 22. The broken line 24 and box25 represent the lens processing apparatus carrying the grinding lap andwhich measures and establishes the surface 26 of the blocking member 20from the lap 22, in a precisely measured relationshi-p, by knowing theestablished size and shape of the grinding lap. It will be seen,therefore, that the lens can be exactly positioned within the blockingmember 20 such that a known dimensional relationship exists between theback surface 26 of the blocking member and the innermost surface 27 ofthe lens 30 which, as illustrated in FIGURE 5, is a convex surface.Accordingly, the lens may be placed in engagement with the grinding lapwhile accurately controlling the thickness of the lens through knowingthe distance of the convex surface 27 of the lens from the surface 28 ofthe grinding lap.

As shown more particularly in FIGURES 2 through 5, the lens blockingmember 20 has a base wall 32 with a front side 34 and a back side 26. Aside wall 36, preferably annular, depends from the front side of thebase wall. In the preferable form of the invention, the side wall 36 hasan annular inwardly facing surface 38 which, together with the frontside 34 of the base wall, forms a cavity 40 therebetween for receiving ablocking agent 42, preferably a low-melting metallic blocking agent, anda lens blank 30.

In the preferred embodiment of the invention, the front side 34 of thebase wall has a concave surface 44 formed thereon approximatelyconforming to the curvature of the convex surface 27 of the lens 30which is inserted into the holder, so as to limit the amount oflow-melting blocking agent needed. It will be appreciated, however, thatthe concave surface of a lens blank may be received 'within the blockingmember such that a convex surface is ground on the exposed or outwardlyfacing surface of the lens blank. In this situation, the front side 34may be convex so as to reduce the amount of required blocking agent.Furthermore, at least one opening or port 46 ex- :tends through the basewall 32 to permit introduction of the low-melting metallic blockingagent into the cavity 40. The blocking member 20 also includes lugs orbosses 50 associated with the base wall for engaging and positionin g alens blank at least partially within the cavity 40 and spaced apredetermined known distance, as at 48, from the back side 26 of thelens blank whereby a precise axial spacing between the inwardly facingsurface 27 on the lens blank and the back side 26 of the blocking membermay be established.

Preferably the lugs 54) are also associated with the side wall, asshown, although it will be appreciated that the lugs 50 may be supportedsolely by the base wall 32 and be positioned inwardly of the side wall.

In one embodiment of the invention the lens blank is engaged andpositioned by a plurality of lugs 50 preferably integrally connected tothe side wall 36 and extending downwardly into engagement with the frontside of the base wall. As illustrated, it will be seen that these lugsare integrally connected with the inwardly facing surface 38 of the sidewall and that there are four lugs equally spaced along this surface.Although it is desirable to have four lugs inasmuch as they preciselyrepresent the extremities of two axes on a compound lens, it will beappreciated that if a spherical lens were being ground, three, live oreven more lugs may be used to position the lens.

It it also within the scope of the invention to have a resilient gasket52 associated with the front side 34 of the base wall 32, for forming asecond cavity 56 concentric within the first cavity 40, with the gasket52 including at least an annular wall 54 extending above the front side34. The annular wall 54 extends sufficiently above the front side so asto engage the lens blank when the lens blank is received within theblocking member. It will be appreciated that the ports 46 communicatewith this second cavity and that the annular wall 54 contains themetallic blocking agent within a smaller volume than the volumerepresented by the first cavity. Furthermore, the metallic blockingagent is prevented from coming between the lens blank and the lugs 50,for a contiguous engagement of the lens and the lugs is essential withinthe scope of the invention. Preferably, the gasket 52 is removable so asto enable replacement whenever it becomes worn out.

As illustrated more particularly in FIGURE 6, the gasket 52 associatedwith the front side comprises an annular base portion 60 and an integralannular flange 62 extending upwardly therefrom. The front side 34 of thebase wall has an annular recess 64 for receiving the base portion 60 ofthe gasket. When the annular base portion is positioned in the recess64, the annular flange 62 extends upwardly and above the front side 34of the base wall into a position for engagement with the lens blank whenthe lens blank is received within the blocking member. In the preferredembodiment of the invention, the annular base portion 60 of the gasket52 has indentations or notches '66 for engaging the lug means 50. Asillustrated, the indentations or notches 66 intersect the outer edge 70of the base portion 65 and receive the lugs 50.

The annular base portion is preferably ring-shaped having an opening 76extending axially therethrough. The ring-shaped base portion has aninner edge 78 and an outer edge 70 adapted to fit contiguously with theinwardly facing surface 38 of the side wall 36. The inner surface 82 ofthe annular flange 62 lies coextensively with the inner edge 78 of thebase portion.

The annular flange 62 has its outer annular edge portion 72 outwardlyflared so as to provide an effective resilient sealing means with theinwardly facing surface of the lens. Furthermore, as illustrated, thebase portion has a substantially greater thickness T than the side walland the thickness T of the side wall decreases as it extends outwardlyfrom the base wall :for optimum sealing effectiveness.

In the preferable form of the invention, as shown in FIGURE 2, theinwardly facing surface 38 has flattened side portions 84 cooperatingwith the flattened edges of the usually square lens blank forpositioning the lens blank in a predetermined orientation within theblocking member. It will be seen that this is particularly important:for orienting lenses within a blocking member when more than one curveis put on the lens surface. If the inwardly facing surface has aplurality of such flat portions, it will also be appreciated that theouter edge 70 of the base portion of the gasket would be correspondinglyflattened so as to fit contiguously therewith.

It is further within the scope of the invention, as shown in FIGURES 2and 3, to include indented openings 88 in the side wall 36 for applyingan instrument means, not shown, inwardly of the side wall to aid inremoving the lens from the low-melting blocking agent. An instrumentmeans, such as a narrow blunt-ended metal rod, is inserted inwardly ofthe side wall and under the lens so that the lens may be knocked freefrom the low-melting metallic blocking agent by a sharp rap on top ofthe rod. It will also be appreciated that the outwardly flaring edge 72can provide a buffer between the instrument rod and the lens blankduring this removal operation so as to prevent the lens from beingdamaged.

The back side 26 of the base wall 32 provides support means for mountingthe lens blocking member on a lens processing apparatus in apredetermined desired orientation. Basically, the desired orientationwith respect to the thickness of the lens is determined by the fact thatthe lugs, and hence the lens surface, are exactly spaced from the backside 26 of the blocking member as previously explained. Thus, thethickness of the lens blank is controlled by supporting the back side ina known predetermined spaced orientation from the surface 28 of thegrinding lap 22. However, it will be appreciated that in order tocontrol the generation of two or more curved surfaces or the generationof a lens having a prismoidal thickness, it is necessary to provide ameans by which the lens may be additionally oriented. Therefore, asillustrated, a raised handle member 94 depending from the back side 26of the base wall 32 is provided which enables the blocking member to begripped in an oriented position. The handle means has keying means 96,such as one or more flat sides, associated therewith so that thesupporting element of the lens processing apparatus can maintain thelens block in a predetermined desired orientation. It will beappreciated that within the scope of the invention the raised handlemember may have various configurations other than those disclosed in thedrawings which will accomplish the objects of the invention.

It is further within the scope of this invention to insert a conicalspindle receiving means 98, preferably within the handle member, so thatin some operations the lens blocking member may be mounted thereby. Theconical spindle receiving means 98 is preferably radially centered withrespect to the annular inwardly facing surface 38 of the side wall. Theblocking member is supported by a spindle, not shown, received withinthe conical spindle receiving means Q8 when it is desirable, forinstancefto remove part of the lens surface uniformly.

FIGURES '7 through 9 illustrate a modified blocking member 20a which ispreferably used in grinding spherical curves on a lens blank. Asillustrated, the blocking member 20a differs from the blocking member2%) disclosed in FIGURES 2 through in that lugs 50 for engaging andpositioning the lens blank are replaced by an annular led-ge 100adisposed above the front side 34a of the base wall 32a and associatedwith the base wall 32a and more particularly the back side 26a of thebase wall 32a so that a precise axial spacing between a surface of thelens blank and the back side 26a may be established. In the preferredform of the embodiment the ledge 100a is integrally connected to theinwardly facing surface 38a of the side wall 36a and extends radiallyinwardly and axially downwardly into engagement with the front side 34aof the base wall 32a. As illustrated, the inwardly facing surface mayhave substantially flat portions 85a for orienting the lens within theblocking member. The means 88a comprises an indented opening 90a whichextends inwardly of the side wall and extends below the surface 102a ofthe annular led-ge ltlila for applying an instrument. Furthermore, asshown more particularly in FIG- URE 9, the raised handle member 94a maybe annular inasmuch as it is not necessary to have a precise orientationfor the establishment of a spherical curve on the surface of the lens. Aconical spindle receiving means 98a may also be received within theraised handle means 94a. Furthermore, similar to the first embodiment ofthe invention, there is at least one opening or port 46a extendingthrough the base wall and communicating with the cavity 40a formedbetween the front side 34a of the base wall and the side *wall 36a.

As illustrated in FIGURE 10, one further feature of this invention isthe fact the side wall 36 of the blocking member is so configured thatit extends beyond the edge of the lens blank during the polishingprocess. When ground to the ultimate desired thickness, it may benecessary to grind away some of the side wall of the blocking member, asillustrated at 102, such that the outer edge of the side wall conformsto the curved surface being ground on the lens. During the polishingoperation this side wall protects the outer edge 104 of the lens frombeing slightly rounded off due to impingement of the lens leading edgeon the polishing pad 106. Even though the outer edge of the lens blankmay be removed before actual use, nevertheless the rounding of this edgemight cause an aberration which lowers the quality rating of the lens.The protective side wall of the blocking device 2t, avoids thisaberration by depressing the polishing pad prior to its contact with thelens itself.

While a preferred form of the invention has been illustrated in thedrawings and discussed above, it should be adequately clear thatconsiderable modifications may be made thereto without departing fromthe principles of the invention. Therefore, the foregoing should beconsidered in an illustrative sense rather than a limiting sense, andaccordingly the extent of this invention should be limited only by thespirit and scope of the claims appended hereto.

What is claimed is:

1. A lens blocking member for holding a lens blank and for use with alens blocking system of the character described employing a blockingagent comprising: a base wall having front and back sides and acontinuous periph ery; a relatively rigid side wall depending from saidfront side, integrally formed therewith, and joined to said base wallthroughout substantially all of the periphery of said base wall, saidside wall having an annular inwardly facing surface, said inwardlyfacing surface and said front side defining a first cavity within whicha lens blank is adapted to be peripherally enclosed; axially centrallylocated mounting means associated with said back side of said base wallfor mounting said lens blocking member on a lens processing apparatus ina predetermined desired orientation; means associated with said basewall adapted to engageand position said lens blank within said firstcavity; and means associated with said front side of said base wallforming a second cavity concentrically within said first cavity, saidmeans including at least a flexible annular wall extending above saidfront side and adapted to engage said lens blank when said lens blank isreceived within said blocking member.

2. The blocking member as defined in claim 1 wherein said base wall hasat least one port extending therethrough for enabling said blockingagent to be inserted into said first cavity through said base Wall.

3. The blocking member as defined in claim 1 wherein said side wallincludes means for applying an instrument means inwardly of said sidewall to aid in removing said lens blank from said low-melting metallicblocking agent.

4. The blocking member as defined in claim 3 wherein said instrumentapplying means comprises an opening extending through said side wall forinserting an instrument means inwardly of said side wall to aid inremoving 5. The blocking member as defined in claim 1 wherein said meansassociated with said front side is removable so as to enablereplacement.

6. The blocking member as defined in claim 1 wherein said meansassociated with said front side comprises resil ient gasket means havingan annular base portion and an integral annular flange extendingupwardly therefrom and wherein said front side of said base wall has anannular recess formed therein for receiving said annular base portion ofsaid gasket means, said annular flange extending upwardly and above saidfront side into a position for engagement with said lens blank when saidlens blank is received within said blocking member.

7. The blocking member as defined in claim 6 wherein said gasket meanscomprises an annular base portion having an edge means for receivingsaid means for engaging and positioning said lens blank within saidfirst cavity, and an annular wall portion integrally depending from saidbase portion and having its outer annular edge portion outwardly flared.

8. The blocking member as defined in claim 7 wherein said gasket meanscomprises a base wall having an outer edge with a plurality ofsubstantially fiat edge portions and a plurality of recessesintersecting said edge for receiving said means for engaging andpositioning said lens blank within said first cavity, and an annularside wall integrally depending from said base wall having its free outerannular edge portion outwardly flared.

9. The blocking member as defined in claim 1 wherein said lens blankengaging and positioning means comprises a plurality of lugs connectedwith said inwardly facing surface.

10. The blocking member as defined in claim 9 wherein there are fourlugs equally spaced along said inwardly facing surface.

11. The blocking member as defined in claim 1 wherein said means formounting said lens blocking member on a lens processing apparatus in apredetermined desired orientation comprises the back surface of saidbase wall and a raised handle member depending from said back surface.

12. The blocking member as defined in claim 11 wherein said raisedhandle member has keying means for enabling said blocking member to bepositioned in a predetermined orientation.

13. The blocking member as defined in claim 12 wherein said keying meanscomprises said handle member having at least two straight parallel sidewall portions by "which said blocking member can be gripped.

14. The blocking member as defined in claim 11 wherein said mountingmeans additionally comprises a conical spindle receiving means rigidlysecured in said raised lhandle member.

15. The blocking member as defined in claim 14 wherein said spindlereceiving means is radially centered with respect to said annularinwardly facing surface of said :side wall.

16. A lens blocking member for holding a lens blank and for use with alens blocking system of the character described employing a blockingagent comprising: a base wall having front and back sides and acontinuous periphery; a relatively rigid side wall depending from saidfront side, integrally formed therewith, and joined to said base wallthroughout substantially all of the periphery of said base wall, saidside wall having an annular inwardly facing surface, said inwardlyfacing surface and said front side defining a first cavity within whicha lens blank is adapted to be peripherally enclosed; axially centrallylocated mounting means associated with said back side of said base wallfor mounting said lens blocking member on a lens processing apparatus ina predetermined desired orientation; means associated with said basewall having a portion thereof defining a second cavity within said firstcavity and another portion thereof defining support means adapted tosupport said lens blank, said base wall having at least one portextending therethrough for enabling a blocking agent to be inserted intosaid second cavity through said base wall; and means defining aninstrumentreceiving opening through said side wall into said firstcavity and partially into said portion defining said support means sothat an instrument can be positioned outside said second cavity and inengagement with a surface of said lens blank when said lens blank ispositioned within said first cavity for removing said lens blank fromsaid lens blocking member.

17. The blocking member as defined in claim 16 wherein said front sideof said base Wall has a concave surface.

18. The blocking member as defined in claim 16 wherein said annularinwardly facing surface has means adapted to cooperate with the edge ofsaid lens blank for positioning said lens blank in a predeterminedorientation within said blocking member.

19. The blocking member as defined in claim 18 wherein said positioningmeans comprises said inwardly facing surface of said side wall having atleast a portion thereof comprising opposed parallel surfaces adapted toengage and hold said edge of said lens blank in a predeterminedorientation within said blocking member.

20. The blocking member as defined in claim 16 wherein said lens blankengaging and positioning means comprises an annular ledge disposed abovesaid front side of said base wall and integrally connected with saidinwardly facing surface of said side wall.

21. In a lens blocking member for use with a lens blank blocking systemhaving a base wall with front and back sides, a relatively rigid sidewall depending from said front side defining a cavity between said sidewall and said front side of said base wall adapted to receive a lensblank, and an axially centrally located mounting means associated withsaid back side for mounting said lens blocking member on a lensprocessing apparatus, the improvement comprising: means associated withsaid front side of said base wall having a flem'ble annular flangedepending from said front side and defining second cavity meansconcentrically within said first cavity, said annular flange adapted toengage said lens blank when said lens blank is received within saidholder, said second cavity means constructed and arranged to receive ablocking agent, and means defining a conduit between the exterior ofsaid blocking member and said second cavity means for permitting theblocking agent to be inserted into said second cavity means.

22. The improvement as defined in claim 21 wherein said cavity definingmeans associated with said front side is removable so as to enablereplacement.

23. The improvement as defined in claim 21 wherein said second cavitydefining means associated with said front side includes an annularring-like base member integrally connected to said annular flange andwherein said front side of said base wall has an annular recess formedtherein for receiving said annular base member.

24. The improvement as defined in claim 21 wherein said annular flangehas its free outer annular edge portion outwardly flared.

25. A gasket for use with blocking members employing a blocking agentcomprising: base means having at least an outer edge, a front side and arear side, and an annular side wall depending from said front side ofsaid base means and having its outer annular edge portion outwardlyflared, said annular side wall defining a central space radiallyinwardly thereof and said base means having means defining an axiallydirected opening communicating said rear side of said base means withsaid space; said base means being ring-shaped having an inner edge andan outer edge, and wherein the inner surface of said side wall iscoextensive with said inner edge.

26. The gasket as defined in claim 25 wherein the thick- 9 ness of saidbase means is substantially greater than the thickness of said sidewall.

27. A gasket for use with blocking members employing a blocking agentcomprising: base means having at least an outer edge, a front side and arear side, and an annular side wall depending from said front side ofsaid base means and having its outer annular edge portion outwardlyflared, said annular side wall defining a central space radiallyinwardly thereof and said base means having means defining an axiallydirected opening communicating said rear side of said base means withsaid space; said outer edge of said base means having a plurality ofsubstantially fiat edge portions and a plurality of indentationsintersecting said edge portions for engaging complementary surfaces ofthe blocking member.

References Cited UNITED STATES PATENTS 1,119,111 12/1914 PelloW 51-2162,264,392 12/1941 McClernon 51217 2,441,472 5/ 1948 DAvaucourt 512162,597,543 5/1952 Suben 51-216 X 3,032,936 5/1962 Voice 51216 X 3,192,6767/1965 Buckminster 5l--216 FOREIGN PATENTS 162,308 2/1949 Austria 51217HAROLD D. WHITEHEAD, Primary Examiner.

16. A LENS BLOCKING MEMBER FOR HOLDING A LENS BLANK AND FOR USE WITH ALENS BLOCKING SYSTEM OF THE CHARACTER DESCRIBED EMPLOYING A BLOCKINGAGENT COMPRISING: A BASE WALL HAVING FRONT AND BACK SIDES AND ACONTINUOUS PERIPHERY; A RELATIVELY RIGID SIDE WALL DEPENDING FROM SAIDFRONT SIDE, INTEGRALLY FORMED THEREWITH, AND JOINED TO SAID BASE WALLTHROUGHOUT SUBSTANTIALLY ALL OF THE PERIPHERY OF SAID BASE WALL, SAIDSIDE WALL HAVING AN ANNULAR INWARDLY FACING SURFACE, SAID INWARDLYFACING SURFACE AND SAID FRONT SIDE DEFINING A FIRST CAVITY WITHIN WHICHA LENS BLANK IS ADAPTED TO BE PERIPHERALLY ENCLOSED; AXIALLY CENTRALLYLOCATED MOUNTING MEANS ASSOCIATED WITH SAID BACK SIDE OF SAID BASE WALLFOR MOUNTING SAID LENS BLOCKING MEMBER ON A LENS PROCESSING APPARATUS INA PREDETERMINED DESIRED ORIENTATION; MEANS ASSOCIATED WITH AID BASE WALLHAVING A PORTION THEREOF DEFINING A SECOND CAVITY WITHIN SAID FIRSTCAVITY AND ANOTHER PORTION THEREOF DEFINING SUPPORT MEANS ADAPTED TOSUPPORT SAID LENS BLANK, SAID BASE WALL HAVING